Apparatus for providing a representation of celestial bodies

ABSTRACT

A Copernican planisphere for providing an indication of stars visible from a particular latitude on a predetermined date at a selected time and the method of operation thereof is disclosed. The planisphere structure and method of operation disclosed facilitates understanding of the Copernican principles of the relation of the heavenly bodies, accurate estimation of moon phases, and the determination of the time before which a particular heavenly body will appear at a viewing meridian, the rising and setting time of a heavenly body, the declination of heavenly bodies and the altitude thereof. Both astronomical and navigational information are provided on the planisphere disclosed. The planisphere structure includes a plurality of concentric dials, which are progressively larger in diameter downwardly, centrally mounted for relative rotation on a pivot pin. The upper dial is a mask through which a portion of the dial below is viewable. The mask includes an indicator portion having a window therethrough extending radially outwardly over the remainder of the dials. A reference rule is pivotally mounted centrally of the dials at one end and extends radially beyond the outer diameter of the larger of the dials. The reference rule is positioned between the mask and adjacent dial.

United States Patent 3,673,710 Eisenhauer 1 *July 4, 1972 [54] APPARATUS FOR PROVIDING A 2,478,981 8/1949 Randall ..35/44 REPRESENTATION ()F CELESTIAL 2,543,815 3/l95l Waller et al. ..35/44 BODIES 3,290,799 l2/l966 Eisenhauer ..35/44 [72] Inventor: William A. Eisenhauer, Van Wert, Ohio FOREIGN PATENTS OR APPLICATIONS 731 Assignees: William A. Eisenhauer; William P. Eisen- 822.910 11/1951 Germany hall; [d8 L Trust; Leigh Eismhauer, 882,320 7/1953 Germany... ...35/44 C 595,089 1 H1947 Great Britain ..35/44 Notice: The portion of the term of this patent subprimary Emmin, jemme Schna" sequent w 13, 1983. has been Allorney-Whittemmqllulbert and Belknap claimed.

22 Filed: Jan. 5, 1970 [571 ABSTRACT A Copernican planisphere for providing an indication of stars [21 1 Appl' 500 visible from a particular latitude on a predetermined date at a Related s Application Data selected time and the method of operation thereof is disclosed. The planisphere structure and method of operation l l cohllhllatloh Q- 1966i disclosed facilitates understanding of the Copernican princiwhlch a commuahon'm'part of 369,953. ples of the relation of the heavenly bodies, accurate estimation M y i 1 which 15 a of moon phases, and the determination of the time before hhuahoh-lh'part of 271,658, APril 9, 1953. which a particular heavenly body will appear at a viewing which is a continuation-impart 0f meridian, the rising and setting time of a heavenly body, the 9, 1959, 1 declination of heavenly bodies and the altitude thereof. Both astronomical and navigational information are provided on 'U-S. [he planisphere disclosed. [5H Int. Cl ....G09b 27/04, 60% 29/00 [58] Field of Search ..35/43, 44, 39; 58/3, 42.5, The plah'sphcre f Includes P i 58/43. 235/78 als, which are progressively larger in dlameter downwardly, centrally mounted for relative rotation on a pivot pin. The [56] References Cited upper dial is a mask through which a portion of the dial below is viewable. The mask includes an indicator portion having a UNlTED STATES PATENTS window therethrough extending radially outwardly over the remainder of the dials. A reference rule is pivotally mounted l,5l3,3l7 l0/l924 Frakes ..58/43 centrally of the dials at one end and extends radially beyond 1,873,595 8/l932 Johnson "35/44 the outer diameter of the larger of the dials. The reference 1,925,233 9/1933 p 58/43 X rule is positioned between the mask and adjacent dial. 2,337,545 l2/l943 Collins ..35/44 2,394,226 2/1946 Baldocchi ..235/78 7 Claims, 2 Drawing Figures TR NS IT 5 PATENTEnJuL'4 um 3.673.710

5 16 5 e a 4 f 28 22 lo G 2 INVENTOR.

WILLIA A. ElSENHAUER ATTORNEYS APPARATUS FOR PROVIDING A REPRESENTATION OF CELESTIAL BODIES This application is a continuation of application Ser. No. 600,920 filed Dec. 12, 1966, now abandoned, which is a continuation-in-part of my application Ser. No. 369,958, filed May 25, 1964, U.S. Pat. No. 3,290,799 which is a continuation-in-part of my prior application Ser. No. 271,658, filed Apr. 9, 1963, U.S. Pat. No. 3,251,143, which is a continuation-in-part of my prior application Ser. No. 85l,648, filed Nov. 9, 1959, U.S. Pat. No. 3,088,228.

The invention relates to planispheres and refers more specifically to a Copernican means for and method of estimating the rising and setting time and approximate position of celestial bodies and more exactly indicating moon phases which Copernican means is useful in navigation.

The Copernican theory in which it is considered that the earth moves around the sun while rotating on its own axis in contrast to the Ptolemaic theory of a fixed earth and a moving sun has long been established. Despite this, most planitariums today operate on a Ptolemaic principle and many books which attempt to teach the layman resort to a Ptolemaic technique when they explain the working and mathematics of time. In addition, in operation of most planispheres, the sky representation is turned more or less promiscuously so that it may appear that the sun rotates about a fixed earth. This is undesirable in that it leaves a false impression in the mind of the user.

In addition the presently available planispheres have not been constructed to provide maximum available information with the least difficulty for the user. Thus with present planispheres no method has been suggested or means provided for rapidly and accurately determining for example the approximate rising and setting time of the sun or the approximate altitude, declination or hour angle of the sun or other heavenly bodies.

In addition prior planispheres have not generally been suitable for use as navigational aids. Thus, important navigational features, such as meridians, sun indication, Greenwich G.I-I.A. indication, indications of celestial bodies and points such as the first point of Aries have been missing from many prior planispheres.

It is therefore an object of the present invention to provide an improved planisphere and method of operation thereof.

A more specific object is to provide means for and a method of determining the approximate rising and setting time of a celestial body.

Another object is to provide means for and a method of determining the approximate altitude or declination of a celestial body.

Another object is to provide an improved means for and method of indicating moon phases.

Another object is to provide a planisphere as set forth above adapted for use as an aid to celestial navigation.

Another object is to provide means for and a method of direct read-out of meridian on local hour angle for astronomy and/or navigation.

Another object of the present invention is to provide a means and method as set forth above which is simple, economical, and efiicient.

Other objects of the invention will become more apparent as the description proceeds, especially when the description is taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a partial plan view of the planisphere of the invention.

FIG. 2 is a partial elevation view of the planisphere illustrated in FIG. 1 taken in the direction of arrow 2 in FIG. 1.

With particular reference to the figures of the drawing, one embodiment of the present invention will now be considered in detail.

As shown best in FIG. 2, the planisphere includes a sky map on date dial 12, a horizon control mask 14, local and standard time dials 16 and 18, a navigation dial 20 and 28 and 32 day moon phase dials 22 and 24 respectively. A reference rule 26 is positioned between the sky map 12 and the mask 14.

Each of the dials l2, l6, 18, 20, 22, and 24 and the mask 14 and reference rule 26 are secured together by and mounted for concentric rotation about the pivot pin 28.

In operation the local time dial, sky map and mask may be manipulated in a completely Copernican manner to provide an indication of the celestial bodies viewable at any selected time on any predetermined date. With the further aid of the reference rule, the local time dial, sky map and mask may be manipulated to provide the approximate rise and setting time of a celestial body and to estimate its altitude and inclination. In addition the local time dial together with the moon phase dials 22 and 24 may be used to estimate the moon phase for any predetermined day and the navigation dial 20 may be used in conjunction with the reference rule and date dial and mask to solve navigation problems and the like. The standard time dial is provided to permit use of standard or watch time in conjunction with the planisphere 10.

More specifically, the sky map 12, as shown best in FIG. 1, includes centrally thereof as viewed through the horizon con trol mask 14 24 radial reference lines and a lesser number of concentric reference lines 30 and 32 which divide the celestial body representation including the stars 34 on the sky map 12. The lines 30 are meridians of right ascension and the lines 32 are parallels of declination. The stars 34 provide a complete polar picture of the heavenly bodies on the sky map 12 with the celestial pole at pin 28. A radial line 36 on mask 14 represents the South meridian line, or the prime meridian of the observer. Concentric line 38 on the mask 14 represents the celestial equator, while the dashed line 40 on the date dial 12 represents the ecliptic or the apparent path of the sun through the celestial bodies caused by the movement of the earth about the sun in accordance with Copernican principles.

Radially outwardly of the indicia of the heavenly bodies on the sky map an annular date scale 42 is provided including an indication of the days of each separate month. Radially outwardly from the date scale 42 on the sky map the scale 44 is provided indicating the Zodiac signs. Outwardly of the Zodiac scale 44 a third scale 50 is provided on the sky map 12 which includes right ascension hour and degrees indicia on the radially inner and outer sides thereof.

The horizon control mask 14 includes the transparent portion 46 outlined by the horizon representation 48 representing the horizon of an observer on the indicated South meridian 36 at a predetermined latitude of, for example 42 North. A degree scale extending in both directions from the concentric line 38 is provided on the meridian 36 of the mask 14 and a time or hour and a degree scale is provided on the concentric line 38 on the mask 14. The mask 14 further has an opaque portion 52 for masking from view those celestial bodies not visible from the indicated location on a predetermined day at a selected time as will be seen subsequently.

In addition the mask 14 includes the indicator portion 54 having window 56 therein through which scales on the dials 12, 16, 18, 20, 22, and 24 may be read in conjunction with the indicator line 58. As illustrated the scales of dials 12, 16, 18, 20, 22, and 24 are named on the indicator portion of the mask 14.

The dial 22 includes the 28-day or 7-day quarter-moon phase scale 60 thereon for use in conjunction with the moon phase indications on the local time dial 16 as will be seen subsequently. The scale 60 is broken up into 28 separate sections. Similarly the moon phase dial 24 is provided with a 32-day or 8-day quarter-moon phase scale 62 thereon broken up into 32 separate sections for use in conjunction with the moon phase indications on the local time dial.

The local time dial 16 is provided around the outer periphery thereof with a time scale 64 which breaks the time of each day into the usual 24-hour periods. As illustrated there is also provided on the local time dial the inner 28-day or 7- days per quarter-moon phase indications 66 for use with moon phase dial 22 and smaller 32 day moon phase indications 67 for use with moon phase dial 24.

The standard time dial 18 is again provided with a time scale 69 which is divided into 24 parts representing the hours of the day. In use the standard time dial 18 may be rotated about the pin 28 relative to the local time dial 16 a distance determined by the distance of the user of the planisphere from a standard time meridian and fixed in this relation so that watch time of the user may be used in conjunction with the planisphere 10 rather than local time. In other words the local time scale 64 on the local time dial l6 and the time scale 69 on the standard time dial 18 provide a means for automatically converting between local and standard time.

The navigation dial 20 includes scales 68 and 73 calibrated in increments in opposite directions as shown. The scales 68 and 73 of dial are useful in establishing measurements such as angular distances in conjunction with the indicator 58 and reference rule 26 for use in navigation.

The reference rule 26, as shown, is transparent and has the radially extending indicating line 70 thereon on which the declination or latitude degrees above and below the concentric circle 38 are marked in ten degree increments, as shown. The outer end of reference rule 26 is adapted to fit within the recess 74 in the lower surface of the outer end of the indicator portion 54 of the mask 14 when it is not in use.

In using the planisphere 10 in a Copernican fashion to provide a view of the stars visible on a predetermined day at a selected time, the day indicated on the scale 42 of the sky map 12 is oriented to the position of the earth about the sun on that day, that is the sky map is rotated until the predetermined date is positioned opposite the sun indication 75 on the local time dial which is diametrically opposite the full moon indication on the local time dial 16.

Having thus determined the position of the earth in its yearly movement about the fixed sun, the horizon control mask 14 is rotated until the indicator line 58 is at a selected time of day on the scale 64, that is to say that the earth must be rotated relative to the sun on the particular day to present the celestial bodies visible on the predetermined day at the selected time which controls the transparent portion 46 of the mask 14 as defined by the line 48.

Thus, it will be seen that as first set forth by Copernicus, the planisphere 10 requires first positioning the sky map 12 relative to the fixed sun indication on the local time dial 16 in accordance with the position of the earth relative to the sun on the day predetermined and subsequently rotating the earth as depicted by the horizon control mask 14 to provide the view of the heavens presented as the earth rotates on its axis. The operation of the planisphere 10 to provide a picture of the heavenly bodies as seen on a predetermined day at a selected time thus leaves no misconception of the Copernican character of the celestial bodies.

In operation of the planisphere 10 to determine the rising and setting time of a celestial body, such as the sun for example, on a particular day, it is necessary to again place the predetermined day on the sky map 12 opposite the sun indication on the local time dial 16 to arrive at the day in question. The horizon control mask 14 is then rotated to align the indicator line 58 with the twelve noon indication of the local time dial, that is in line with the sun indication thereon. The indicator line 58 thus establishes the point at which the ecliptic 40 crosses the observers prime meridian or in more general terms establishes the transit of the South meridian of the observer by the sun.

The mask 14 is then rotated clockwise until the setting limit Western horizon as indicated thereon coincides with the established ecliptic point. The indicator line 58 will then read on the local time dial the time of setting of the sun on the predetermined day. Counterclockwise movement of the mask 14 would establish the rising time of the sun on the predetermined day on the local time dial as indicated by the indicator line 58 when the rising limit Eastern horizon of the mask 14 coincides with the established point on the ecliptic. The point at which the observers prime meridian crosses the ecliptic which is the transit position of the sun must be maintained by use of the reference rule 26 during this operation.

Similarly it is only a matter of finding the transit position of any other heavenly bodies and rotating the mask ninety degrees in either direction from transit of the observer's South meridian by the other heavenly bodies to locate the rising and setting time of the other heavenly bodies on the local time dial. The reference rule 24 must also be used to maintain the transit position of the other heavenly bodies when determining the rising and setting time thereof.

The declination of the sun on the predetermined date is determined with the planisphere 10 by measuring in degrees with the radial degree scale on prime meridian 36 on the mask 14 the separation between the equator concentric line 38 and the ecliptic line 40 on the sky map 12 with the predetermined date on which it is desired to know the declination of the sun set opposite the fixed sun designation on the local time dial and the mask 14 positioned at 180 to the position shown.

The altitude of the sun in degrees at this time is then the degree measurement between the ecliptic and the horizon on the prime meridian. Thus, it can be seen that the planisphere 10 is useful in determining the approximate declination and altitude of heavenly bodies. Compensation can be readily interpolated for latitudes other than 42 North by considering horizon limits accordingly, that is North or South of the actually known latitude position of the observer.

In determining an approximate moon phase which will occur on a predetermined day with the planisphere 10, an almanac or local paper giving astronomical information is first consulted to determine on what exact date the nearest previous quarter moon appeared and whether or not there are seven or eight days between the nearest previous moon quarter indicated in the almanac or paper and the next occurring moon quarter. The 28-day or 32-day moon phase dial 22 or 24 respectively, depending on whether it is 7 days between the previous quarter and next quarter-moon or 8 days between the previous quarter and next quarter-moon, is then rotated to place the known quarter indication on the local time dial 16 adjacent the respective moon scales 66 or 67.

The number of days since the previous quarter moon for the predetermined date, as indicated in the almanac or paper, is then counted clockwise on the respective scale 60 or 62 and the moon phase indication for the date in question will then be illustrated opposite the last counted division on the scale 60 or 62 on the moon phase scales 66 or 67 respectively. Thus rapid approximation of the moon phase on any given day is possible with the planisphere 10.

Conversely and possibly of more importance, once the moon phases are locked into the solar dial on a spatial but always true relationship with the sun, the 7- and 8-day quarter increment scales 60 and 62 may be used to date the phases which are generally known from the papers and almanacs.

Thus the dials 22 and 24 provide a variable adjustable and compensating dial system for keeping track of the phase of lunar month days. That is to say, it is possible to shift back and forth between the 7- and 8-day quarter increments to coincide with months having 29 mo 29%days. Interpolation of quarter days is also possible. From exact position measurements reference is made to the nautical almanac.

As previously indicated the local time may be readily converted to standard time by merely adjusting the standard time dial with respect to the local time dial in accordance with the distance of the user of the planisphere 10 East or West from the standard time meridian and reading directly from the scale 64 on the local time dial to the scale 69 on the standard time dial or reverse. Thus standard or watch time may be used with the planisphere 10 if desired.

Using the horizon control mask 14 having the South line 36 and indicator line 58 which is an extension of the South meridian line 36 and the time and degree scale 38 with the zero position on the meridian line 36 thereon, the sky map 12 and the reference rule 26, the meridian angle of any celestial body may be directly determined. Thus to determine the meridian angle of any celestial body, it is merely necessary to place the meridian line 36 or indicator line 58 on the desired time on local time dial scale 64 after orienting the local time dial by programing the sun to the date on the sky map dial l2 and turn the reference rule 26 to the celestial body in question and read the meridian angle of the celestial body from the scale 38 beneath the reference rule 26.

With the indicated ability to measure meridian angle readily, the planisphere l0 lends itself to use as a navigational aid as well as an astronomical tool. Thus, in navigation the distance between the prime meridian of the observer indicated by M and a sky objects position, as indicated by the reference rule either as it crosses a position point on the sky map or marks a degree distance on an appropriately placed scale serves to produce the desired distance measurement for either astronomical or navigational purposes.

For use as a navigational aid, the planisphere includes the star references 34, a reference 80 for the first point of Aries on the date dial 12, a sun indication 75 on dial l6 and navigation East and West degree scales 68 and 73 on the dial 20. These in conjunction with the reference rule 26 and indicator portion 54 of the mask 14 permit relatively easy plotting of navigational time diagrams, such as suggested in the handbook Navigation the Easy Way by Carl D. Lane and John Montgomery, published by W. W. Norton & Company, Inc., N. Y., 1949. In this regard it will be readily understood that with the information provided on the planisphere 10 that the use of the planisphere 10 as an aid in navigation will be restricted only by the imagination of the navigator.

With further regard to use of the planisphere as a navigational aid, it will be noted that the navigation dial can be used substantially independently of the planisphere as such to provide a diagram as depicted in the above referenced publication for establishing the pertinent time increments for the sun, moon, stars and planets.

Thus it will be seen that there has been provided in accordance with the invention as exemplified by the structure and methods disclosed above a planisphere which is inherently Copernican in nature and which is organized to provide a continuous but true South reference point once the South meridian is free to indicate it properly subject to the locked in fixed sun position that provides proper orientation of the time control for every moment on a particular day. By providing a solar dial that employs the Copernican mechanics involved, the user is left with no other conclusion than to accept and be forced to recognize the daily locked in feature of the sun and for that matter the stars into a fixed position. Wherever the sun is, it is forever noon and only the turning of the earth provides the time scale for any location on the earth as it processes its spatial relationship through the course of the twenty-four hour period involved in the day in point.

Further it will be recognized that with the planisphere structure disclosed including the observers prime meridian line 36, indicator line 58, scale 36 and the reference rule 26, any arrangement of position or time difference between celestial bodies is available on a direct read-out basis.

Also, it will be noted that the general public, being better educated to Copernican principles due to the space program than they have been since the establishment of Copernican principles, are better prepared to accept Copernican principles which have been accepted by astronomers for centuries. This is true even in view of certain egocentric conclusions concerning the importance of the individual and the centering and movement of the universe about the earth.

The planisphere of the invention should therefore provide an excellent astronomical instruction tool and tool for approximate astronomical observations or calculations and navigation aid. The fact that the approximations provided by the planisphere of the invention can be precisely provided when, for example, the Nautical Almanac readings are employed and programed in accordance with the G.H.A. readings as of a particular moment of G.M.T. will not detract from the use of the planisphere as an instructional aid or quick estimate or check of the more detailed calculations. In fact, the latter implements the other approach to supplement and fortify the acceptance of the fact that the aforesaid approximations are legitimate procedures otherwise. It will however be noted that the use of the disclosed planisphere as a navigation aid will be somewhat limited by the readily available electronic navigation aids, such as Loran equipment.

While one embodiment of the present invention has been considered in detail, other embodiments and modifications thereof are contemplated by the inventor. it it is therefore the intention to include all embodiments and modifications as are defined by the appended claims within the scope of the invention.

What I claim as my invention is:

l. A planisphere comprising a plurality of substantially flat, concentric dials of progressively larger diameter from the top thereof, pivot means securing the dials together centrally for relative rotation, a sky map of heavenly bodies representative of a celestial sphere having a North Pole at the center of rotation of the dials and an annular date scale around the outer periphery of the second smallest dial, an annular local time scale concentric with and radially outwardly of the date scale on the outer periphery of a third of the dials and sun and moon indications on the local time scale, 28-day moon phase indications on the third dial angularly spaced equally therearound and concentric with the local time scale, a fourth dial having a moon phase scale thereon divided into 28 equal parts concentric with and spaced radially from the moon phase indications on the third dial, the smallest dial being a mask having an opening therethrough representing the horizon of an observer at a particular place positioned over the sky map on the second dial so that the date scale is visible about the periphery thereof, whereby Copernican operation of the planisphere is visualized on movement of the mask over the sky map locked in on a sun location on a predetermined date to provide a representation of the stats visible on the predetermined date at a selected time, an indicator portion extending radially outwardly from the mask beyond the outer diameter of the largest dial having a window therein through which a portion of each of the dials may be viewed and in which a viewing meridian is provided, and a reference rule, one end of which is pivoted on the pivot means extending radially outwardly therefrom beyond the outer diameter of the larger of the dials positioned between the mask of the smallest dial and the sky map of the adjacent dial.

2. Structure as set forth in claim 1 wherein the radially outer portion of the indicator portion of the mask dial is provided with a radially extending channel in the bottom thereof and the reference rule is adapted to fit within the channel in the indicator portion of the mask dial.

3. Structure as set forth in claim 1 and further including a meridian angle scale on the mask and a fifth dial positioned radially outwardly of the other four dials and including scales thereon for navigational use reading clockwise and counterclockwise which in operation after being programmed from mathematical almanac information provide navigation information with accuracy without possibility of mathematical computation error in conjunction with the meridian angle scale and reference rule.

4. A planisphere comprising a plurality of substantially flat, concentric dials of progressively larger diameter from the top thereof, pivot means securing the dials together centrally for relative rotation, a sky map of heavenly bodies representative of a celestial sphere having a North pole at the center of rotation of the dials and an annular date scale around the outer periphery of the second smallest dial, an annular local time scale concentric with and radially outwardly of the date scale on the outer periphery of a third of the dials and sun and moon indications on the local time scale, 32-day moon phase indications on the third dial angularly spaced equally therearound and concentric with the local time scale, a fourth dial having a moon phase scale thereon divided into 32-equal parts concentric with and spaced radially from the moon phase indications on the third dial, the smallest dial being a mask having an opening therethrough representing the horizon of an observer at a particular place positioned over the sky map on the second dial so that the date scale is visible about the periphery thereof, whereby Copernican operation of the planisphere is visualized on movement of the mask over the sky map locked in on a sun location on a predetermined date to provide a representation of the stars visible on the predetermined date at a selected time, an indicator portion extending radially outwardly from the mask beyond the outer diameter of the largest dial having a window therein through which a portion of each of the dials may be viewed and in which a viewing meridian is provided, and a reference rule, one end of which is pivoted on the pivot means extending radially outwardly therefrom beyond the outer diameter of the larger of the dials positioned between the mask of the smallest dial and the sky map of the adjacent dial.

5. Structure as set forthin claim 4 wherein the radially outer portion of the indicator portion of the mask dial is provided with a radially extending channel in the bottom thereof and the reference rule is adapted to fit within the channel in the indicator portion of the mask dial 6. Structure as set forth in claim 4 and further including a meridian angle scale on the mask and a fifth dial positioned radially outwardly of the other four dials and including scales thereon for navigational use reading clockwise and counterclockwise which in operation after being programed from mathematical almanac information provide navigation information with accuracy without possibility of mathematical computation error in conjunction with the meridian angle scale and reference rule.

7. A planisphere comprising a plurality of substantially flat, concentric dials of progressively larger diameter from the top thereof, pivot means securing the discs together centrally for relative rotation, a sky map of heavenly bodies representative of a celestial sphere having a North pole at the center of rotation of the dials and an annular date scale around the outer periphery of the second smallest dial, an annular local time scale concentric with and radially outwardly of the date scale on the outer periphery of a third of the dials and sun and moon indications on the local time scale including 32-day moon phase indications angularly spaced equally therearound and concentric with the local time scale, fourth and fifth dials having moon phase scales thereon divided into 28 and 32 equal parts concentric with and spaced radially inwardly from the moon phase indications on the third dial, a sixth dial having a standard time scale on the radially outer periphery thereof for comparison with the local time scale on the third dial concentric with and spaced radially outwardly of the local time scale, the smallest dial being a mask including a meridian angle scale thereon and having an opening therethrough representing the horizon of an observer in a particular place positioned over the sky map on the second dial so that the date scale is visible about the periphery thereof, whereby Copernican operation of the planisphere is visualized on movement of the mask over the sky map locked in on a sun location on a predetermined date to provide a representation of the stars visible on the predetermined date at a selected time, an indicator mask portion extending radially outwardly from the mask beyond the outer diameter of the largest dial having a window therein through which a portion of each of the dials may be viewed and in which a viewing meridian is provided, and a reference rule, one end of which is pivoted on the pivot means extending radially outwardly therefrom beyond the outer diameter of the dials positioned between the mask of the smallest dial and the sky map of the adjacent dial and a seventh dial positioned radially outwardly of the other dials and including scales thereon for navigational use reading clockwise and counterclockwise which in operation after being programed from mathematical almanac information provide navigation information with accuracy without possibility of mathematical computation error in conjunction with the meridian angle scale and reference rule. 1

* IIK 

1. A planisphere comprising a plurality of substantially flat, concentric dials of progressively larger diameter from the top thereof, pivot means securing the dials together centrally for relative rotation, a sky map of heavenly bodies representative of a celestial sphere having a North Pole at the center of rotation of the dials and an annular date scale around the outer periphery of the second smallest dial, an annular local time scale concentric with and radially outwardly of the date scale on the outer periphery of a third of the dials and sun and moon indications on the local time scale, 28-day moon phase indications on the third dial angularly spaced equally therearound and concentric with the local time scale, a fourth dial having a moon phase scale thereon divided into 28 equal parts concentric with and spaced radially from the moon phase indications on the third dial, the smallest dial being a mask having an opening therethrough representing the horizon of an observer at a particular place positioned over the sky map on the second dial so that the date scale is visible about the periphery thereof, whereby Copernican operation of the planisphere is visualized on movement of the mask over the sky map locked in on a sun location on a predetermined date to provide a representation of the stars visible on the predetermined date at a selected time, an indicator portion extending radially outwardly from the mask beyond the outer diameter of the largest dial having a window therein through which a portion of each of the dials may be viewed and in which a viewing meridian is provided, and a reference rule, one end of which is pivoted on the pivot means extending radially outwardly therefrom beyond the outer diameter of the larger of the dials positioned between the mask of the smallest dial and the sky map of the adjacent dial.
 2. Structure as set forth in claim 1 wherein the radially outer portion of the indicator portion of the mask dial is provided with a radially extending channel in the bottom thereof and the reference rule is adapted to fit within the channel in the indicator portion of the mask dial.
 3. Structure as set forth in claim 1 and further including a meridian angle scale on the mask and a fifth dial positioned radially outwardly of the other four dials and including scales thereon for navigational use reading clockwise and counterclockwise which in operation after being programmed from mathematical almanac information provide navigation information with accuracy without possibility of mathematical computation error in conjunction with the meridian angle scale and reference rule.
 4. A planisphere comprising a plurality of substantially flat, concentric dials of progressively larger diameter from the top thereof, pivot means securing the dials together centrally for relative rotation, a sky map of heavenly bodies representative of a celestial sphere having a North pole at the center of rotation of the dials and an annular date scale around the outer periphery of the second smallest dial, an annular local time scale concentric with and radially outwardly of the date scale on the outer periphery of a third of the dials and sun and moon indications on the local time scale, 32-day moon phase indications on the third dial angularly spaced equally therearound and concentric with the local time scale, a fourth dial having a moon phase scale thereon divided into 32-equal parts concentric with and spaced radially from the moon phase indications on the third dial, the smallest dial being a mask having an opening therethrough representing the horizon of an observer at a particular place positioned over the sky map on the second dial so that the date scale is visible about the periphery thereof, whereby Copernican operation of the planisphere is visualized on movement of the mask over the sky map locked in on a sun location on a predetermined date to provide a representation of the stars visible on the predetermined date at a selected time, an indicator portion extending radially outwardly from the mask beyond the outer diameter of the largest dial having a window therein through which a portion of each of the dials may be viewed and in which a viewing meridian is provided, and a reference rule, one end of which is pivoted on the pivot means extending radially outwardly therefrom beyond the outer diameter of the larger of the dials positioned between the mask of the smallest dial and the sky map of the adjacent dial.
 5. Structure as set forth in claim 4 wherein the radially outer portion of the indicator portion of the mask dial is provided with a radially extending channel in the bottom thereof and the reference rule is adapted to fit within the channel in the indicator portion of the mask dial.
 6. Structure as set forth in claim 4 and further including a meridian angle scale on the mask and a fifth dial positioned radially outwardly of the other four dials and including scales thereon for navigational use reading clockwise and counterclockwise which in operation after being programed from mathematical almanac information provide navigation information with accuracy without possibility of mathematical computation error in conjunction with the meridian angle scale and reference rule.
 7. A planisphere comprising a plurality of substantially flat, concentric dials of progressively larger diameter from the top thereof, pivot means securing the discs together centrally for relative rotation, a sky map of heavenly bodies representative of a celestial sphere having a North pole at the center of rotation of the dials and an annular date scale around the outer periphery of the second smallest dial, an annular local time scale concentric with and radially outwardly of the date scale on the outer periphery of a third of the dials and sun and moon indications on the local time scale including 32-day moon phase indications angularly spaced equally therearound and concentric with the local time scale, fourth and fifth dials having moon phase scales thereon divided into 28 and 32 equal parts concentric with and spaced radially inwardly from the moon phase indications on the third dial, a sixth dial having a standard time scale on the radially outer periphery thereof for comparison with the local time scale on the third dial concentric with and spaced radially outwardly of the local time scale, the smallest dial being a mask including a meridian angle scale thereon and having an opening therethrough representing the horizon of an observer in a particular place positioned over the sky map on the second dial so that the date scale is visible about the periphery thereof, whereby Copernican operation of the planisphere is visualized on movement of the mask over the sky map locked in on a sun location on a predetermined date to provide a representation of the stars visible on the predetermined date at a selected time, an indicator mask portion extending radially outwardly from the mask beyond the outer diameter of the largest dial having a window therein through which a portion of each of the dials may be viewed and in which a viewing meridian is provided, and a reference rule, one end of which is pivoted on the pivot means extending radially outwardly therefrom beyond the outer diameter of the dials positioned between the mask of the smallest dial and the sky map of the adjacent dial and a seventh dial positioned radially outwardly of the other dials and including scales thereon for navigational use reading clOckwise and counterclockwise which in operation after being programed from mathematical almanac information provide navigation information with accuracy without possibility of mathematical computation error in conjunction with the meridian angle scale and reference rule. 